1. Field of the Invention
The present invention relates to an organic EL display device and a method for manufacturing the device.
2. Description of the Related Art
In organic electroluminescent (EL) display devices, the thickness of an organic layer including a light-emitting layer affects its light-emitting performance such as light intensity. Thus, the thickness needs to be managed with high accuracy. JP 2007-88127 A discloses an organic semiconductor device in which an area used to measure the thickness of an organic film (hereinafter, simply “measurement area”), is provided outside its display area. Organic layers are formed in both the display area and the measurement area, and the thickness of the organic layer formed in the measurement area is measured. As a method for measuring the thickness, it is typical to irradiate the measurement area with light and analyze reflected light (e.g., reflection spectroscopy and spectroscopic ellipsometry).
Moisture deteriorates organic layers. Thus, in many organic EL display devices, organic layers formed in their display area are covered with a sealing film to keep out moisture. However, if the organic layer in the measurement area is covered with a sealing film, which is usually several times to several tens of times as thick as an organic layer, the sealing film affects measurement of the thickness of the organic layer and makes it difficult to measure the thickness with high accuracy. In this regard, if the sealing film in the measurement area is removed, moisture may enter the organic layer and affect measurement of the thickness.